genirq: Remove unused CONFIG_GENERIC_PENDING_IRQ_CHIPFLAGS

CONFIG_GENERIC_PENDING_IRQ_CHIPFLAGS is not used anymore, hence remove it.

Fixes: f94a1824 ("genirq: Remove IRQ_MOVE_PCNTXT and related code")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250209041655.331470-7-apatel@ventanamicro.com